JP2002308464A - Image forming device - Google Patents

Abstract

(57) [Problem] To provide an image forming apparatus capable of inverting a sheet on which a plurality of holes are formed without breaking the sheet. A lever member protrudes from a sheet reversing path for reversing a sheet having a plurality of holes formed in a width direction orthogonal to a sheet conveying direction. The sheet is detected by the lever member 62 which rotates while resisting the urging force by the sheet to be performed. Then, a projecting portion 62 a is formed at the projecting end of the lever member 62, and after the sheet conveyed while pressing the lever member 62 or after passing through the lever member 62,
The lever member 62 is prevented from entering the hole of the sheet S conveyed in the sheet reversing path 46 by the urging force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly to an apparatus for forming an image on a sheet having a plurality of holes formed in a width direction orthogonal to a sheet conveying direction.

[0002]

2. Description of the Related Art In a conventional image forming apparatus such as a copying machine or a printer, an image is formed on a sheet and then the sheet is discharged to a paper discharge section. In the case of discharging the sheet, the sheet is reversed and discharged by a sheet reversing path. This sheet reversing pass is also used when performing double-sided printing.

In such an image forming apparatus, a discharge sensor flag is provided in the vicinity of a sheet discharge section, and the sheet discharge timing is used to detect a sheet discharge timing, a jam in the sheet discharge section, and a sheet reversal timing. Is being measured.

FIG. 22 is a perspective view showing the vicinity of a sheet discharge section provided with such a conventional discharge sensor flag, and FIG. 23 is a sectional view thereof. In FIG. 23, reference numeral 91 denotes a discharge sensor flag. Here, when the discharge sensor flag 91 is pressed by a sheet (not shown) conveyed from the direction of arrow A,
It is pushed down as shown by the imaginary line while resisting the spring 91a. The sheet conveyed while pushing down the discharge sensor flag 91 is then discharged by the discharge roller 52A in the direction of arrow B.

The discharge roller 52A is reversible so that the sheet can be turned over. When the sheet is turned over, the discharge roller 52A is turned over.
Is first rotated forward to convey the sheet in the direction of arrow B. During this time, the sheet is temporarily stopped by a signal from a controller (not shown), and then rotated in the reverse direction to reverse the sheet to the reverse discharge roller 53A.
To be transported to As a result, the sheet is discharged in an inverted state by the reverse discharge roller 53A.

By the way, such a discharge sensor flag 9
In the image forming apparatus provided with No. 1, after forming an image on a sheet in which a plurality of holes are formed in the width direction orthogonal to the sheet conveying direction, for example, as shown in FIG. It may be inverted and discharged. The size of the sheet S is 216 × 27.
9 LTR size, the size of the hole Sh is 8 mm in diameter, and the interval between each hole Sh is 108 m
m.

Next, the operation of reversing such a sheet after transporting the sheet with the perforated side as the leading edge will be described with reference to FIGS. 25 and 26. FIG. Sheet S is shown in FIG.
When the sheet S is conveyed to the discharge section as shown in FIG. 4 (b), the sheet S is first conveyed while pushing down the discharge sensor flag 91 at its leading end as shown in FIG. You.

During the sheet conveyance, when the hole Sh of the sheet S passes above the discharge sensor flag 91, the pressing force of the sheet against the discharge sensor flag 91 is lost, so that the discharge sensor flag 91 has a spring 91a (see FIG. 23). ) Is raised by the urging force and enters the hole Sh, but is immediately pressed again by the sheet S and pushed down, so that there is no influence on the conveyance of the sheet S.

Next, the sheet S is moved to a predetermined position as described above.
Is transported once, the discharge roller 52A temporarily stops, and after this, the reverse rotation starts after a predetermined time has elapsed. This allows
The sheet S is conveyed in an inverted state.

By the way, when the sheet S is conveyed reversely and the hole Sh of the sheet S reaches the discharge sensor flag 91 soon, as shown in FIG. 26A and FIG. Is released, and the discharge sensor flag 91 starts to rise due to the urging force of the spring 91a.

When the sheet S is further conveyed in the reverse direction, the discharge sensor flag 91 completely enters the hole Sh, as shown in FIG. Here, if the conveyance of the sheet S is continued while the discharge sensor flag 91 has entered the hole Sh, the sheet S is torn.

[0012]

In order to prevent such tearing of the sheet S, the discharge sensor flag 91 is generally arranged at a position shifted from the center in the sheet conveying direction. The discharge sensor flag 91 is prevented from entering the perforated portion Sa.

FIG. 28 shows a discharge sensor flag 91.
Represents the size of a typical sheet on which an image is formed by the image forming apparatus including the following. According to this, the narrowest sheet is a postcard (100 × 148). Therefore, when conveying the postcard, it is necessary to make the distance between the discharge rollers smaller than 100 mm.

FIG. 29 is a diagram showing an example of this case. In this case, the distance between the central rollers is 51 mm, and the distance between the central rollers is a value determined to some extent in accordance with the size of the sheet. Becomes Therefore, if the discharge sensor flag 91 is to be arranged at a position shifted from the central portion in the sheet conveying direction, the shift amount is limited by the position of the discharge roller 52A.

On the other hand, the positions of the holes of the three-hole sheet may be shifted due to a lateral registration error of the image forming apparatus, a component tolerance of the image forming apparatus, or the like. Also, the size of the hole may be up to 8.2 mm in diameter due to its tolerance. Furthermore, the position of the hole with respect to the sheet is not always in the center,
It may be shifted by about 3 mm.

Therefore, taking these facts into consideration,
A hole displacement of about 10 mm at the maximum occurs. Therefore, even when the ejection sensor flag 91 is arranged at a position shifted from the center in the sheet conveying direction, the hole of the sheet is shifted to the position of the ejection sensor flag 91, and as a result, the sheet is torn when the sheet is inverted. There was a point.

Accordingly, the present invention has been made in view of such circumstances, and has as its object to provide an image forming apparatus capable of inverting a sheet having a plurality of holes formed therein without breaking the sheet. It is.

[0018]

SUMMARY OF THE INVENTION The present invention relates to an image forming apparatus for forming an image on a sheet having a plurality of holes formed in a width direction orthogonal to a sheet conveying direction, wherein the sheet is used for reversing the sheet. A reversing path, a lever member protruding from the sheet reversing path, being pressed by a sheet conveyed to the sheet reversing path and rotating while resisting an urging force, the sheet being rotated by rotation of the lever member A sheet detecting means for detecting whether the sheet is conveyed while pressing the lever member, or after passing through the lever member, the sheet is conveyed in the sheet reversing path in an inverted state, and the lever is inserted into the hole of the sheet. A protrusion is formed at a protruding end of the lever member so that the member does not enter due to the urging force.

Further, the present invention is characterized in that the projecting portion is formed on the side of the projecting end of the lever member in the sheet conveying direction.

Further, in the present invention, the length of the projection in the width direction is set to be longer than the length of the hole of the sheet in the width direction.

Further, the present invention is characterized in that the length of the projecting portion is set longer than the length of the hole of the sheet in the sheet conveying direction.

Further, the present invention is characterized in that the projecting portion is formed at a projecting end of the lever member so as to be substantially horizontal with the sheet conveying direction when the lever member projects into the sheet reversing path. Things.

Further, the present invention is characterized in that a gently curved connecting portion is provided between the projecting portion and a contact surface of the lever member with which the sheet comes into contact.

Further, the present invention is characterized in that the lever member is formed by molding.

Further, in the present invention, the lever member has a parting line on the upper surface of the protruding end, and a step of the parting line has a shape lower in a sheet reversing direction opposite to the sheet conveying direction. It is characterized by the following.

[0026]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view of an image forming apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view of the image forming apparatus viewed from another direction, and FIG. 3 shows a schematic configuration of the image forming apparatus. FIG.

1 to 3, reference numeral 100 denotes an image forming apparatus. The image forming apparatus 100 includes an apparatus main body 101.
An optional paper feed cassette 103 mounted as an option below the apparatus main body 101, a pressure plate 104 mounted on the upper surface of the apparatus main body 101, or an automatic document feeder (optionally mounted on the upper surface of the apparatus main body 101) ADF 102). In addition,
1 and 2 show a state where the pressure plate 104 is mounted on the upper surface of the apparatus main body 101, and FIG. 3 shows a state where the ADF 102 is mounted on the upper surface of the apparatus main body 101.

The image forming apparatus 100 has a function of a copier and a function of a facsimile, and converts image information (optical signal) of a read original into an electric signal to form an image. It is a multifunction machine.

An image forming unit 1 is provided at a substantially central portion of the apparatus main body 101, a paper feeding unit 2 is provided below the image forming unit 1, and a scanner unit 3 which is an image reading unit is provided at an uppermost portion. Note that the apparatus main body 101 according to the present embodiment is
Utilizes the characteristics of a digital machine to separate the image forming unit 1 and the scanner unit 3 and to form a wingless system by forming a paper discharge space 4 with an open side between them, and protrudes to the side of the apparatus. This realizes a space-saving image forming apparatus without the need.

Here, the image forming section 1 is configured as a well-known electrophotographic print engine, and includes an electrophotographic process means 150, a fixing device 151, a laser writing device (not shown), and the like.

The paper supply unit 2 includes a two-stage paper supply cassette 2.
The sheet stored in the sheet cassette 21 or the optional sheet cassette 103 is fed to the image forming section 1. Each paper cassette 2
Reference numerals 1 and 103 denote front-loading type drawers which are pulled out to the front side of the apparatus and replenish sheets, and a pull-out handle is provided at the center of the front surface of the cassette.

The scanner section 3 has a contact glass (not shown) disposed on the upper surface thereof, and a scanner unit (not shown) disposed below the contact glass.

The paper discharge space 4 has two sides except the front and right sides, that is, the left side and the back side in FIG. 3 are surrounded by a wall surface, and the scanner unit 3 and the image forming unit 1 surround the upper and lower sides. Have been. The paper discharge space 4 is provided on a first paper discharge tray 4 provided on the upper surface of the image forming section 1.
1 and a second paper discharge tray 42 provided at the center of the paper discharge space 4.

The ADF 102 is mounted on the upper part of the apparatus main body 101 by a hinge (not shown) provided on the back side of the apparatus.
It is installed so as to cover the contact glass on the upper surface of the scanner unit 3 so that it can be opened and closed and closed.

Here, the configuration and operation of the ADF 102 are the same as those of the conventional ADF, and a detailed description thereof will be omitted. However, when a document bundle (not shown) is set on the document table 71,
The originals are conveyed one by one from below onto the contact glass. After the scanning by the scanner unit 3 is completed, the originals are discharged onto the original discharge table 72.

Note that the ADF 102 can be used as a pressure plate for copying that does not rely on automatic paper feeding, or for copying a book or notebook. When the optional ADF 102 is not mounted, a pressure plate 104 for pressing a document on the contact glass is mounted on the upper surface of the scanner unit 3 as shown in FIGS.

On the other hand, reference numeral 43 denotes a third discharge tray which is a second discharge portion provided on the left outside surface of the apparatus main body 101 at a position opposed to the discharge space 4, and reference numeral 44 denotes a side wall of the discharge space 4. This is an optional paper discharge unit to be formed. Here, the optional discharge unit 44 includes, for example, a copy, a printer,
This unit is capable of performing FAX sorting, and in a case where sorting is required, the apparatus main body 1
01 is detachably mounted.

By providing such an optional sheet discharging unit 44 and, for example, stacking the facsimile sheets on the third sheet discharging tray 43, the total number of sheets to be stacked in the image forming apparatus 100 can be increased. Then, the sheets can be sorted and stacked.

By providing such an optional paper discharge unit 44, the image forming apparatus 100 can have the first to third discharge units 50A, 50B, 50 as shown in FIG.
C will be provided with three discharge units.

The first discharge unit 50A includes a first discharge roller 51, a first discharge sensor flag 61, and a first discharge tray 41, and the second discharge unit 50B includes a second discharge roller 52 and a second discharge sensor. A flag 62 and a second discharge tray 42 are provided, and a third discharge roller 53, a third discharge sensor flag 63, and a third discharge tray 43 are provided in the third discharge portion 50C. The first, second, and third discharge sensor flags 61, 62, and 63 are the first, second, and third discharge sensor flags, respectively.
The discharge rollers 51, 52, 53 are disposed upstream of the discharge rollers 51, 52, 53.

In this embodiment, the first discharge unit 50A is connected to the first discharge roller 5 via the first transport path 47.
1 to discharge the sheet to the first discharge tray 41 and form an image on the back surface of the sheet.
After the sheet is reversed in the discharge unit 50A and is directed from the first transport path 47 to the two-sided path 152, the sheet is again directed to the image forming unit.

The second discharge unit 50B discharges the sheet to the second discharge tray 42 by the second discharge roller 52 via the sheet discharge path 46, and reverses the sheet to form a sheet discharge path serving as a sheet reversing path. After passing through 46, it is directed to the third discharge section 50C via the optional discharge path 45. For this reason, the first discharge roller 51 and the second discharge roller 52 can be rotated forward and backward.

Incidentally, in FIG.
This is a first flapper for switching the transport path between the first discharge section 50A and the second discharge section 50B, and is disposed at the junction of the transport path to the first discharge section 50A and the transport path to the second discharge section 50B. Reference numeral 56 denotes a second flapper that directs the sheet to the second discharge unit 50B, and inverts the sheet that is directed to the second discharge unit 50B and directs the sheet to the third discharge unit 50C. It is arranged at the junction of the transport path to the second discharge section 50B and the transport path to the third discharge section 50C. Reference numeral 58 denotes a third flapper that directs the sheet inverted in the first discharge unit 50A to the two-sided path 152.

Here, the first flapper 55 is driven by a solenoid (not shown) and is configured to be rotatable in the direction of arrow G. The second flapper 56 is urged rightward by an arrow F by a spring (not shown), and is rotated leftward by the arrow F by being pushed up by the sheet. The third flapper 58 is urged to the right in the direction of arrow M by a spring (not shown), and is rotated leftward by arrow M by being pushed up by the sheet.

FIG. 5 is a perspective view showing the vicinity of the second discharge portion, and FIG. 6 is a sectional view thereof. Here, as shown in FIGS. 5 and 6, the second discharge sensor flag 62 which is a lever member is used.
Is projected to the sheet discharge path 46 and urged by a spring 64 in a direction opposite to the sheet conveying direction. Also,
The second discharge sensor flag 62 is integrally provided with a rotating shaft 62d, and further, at one end of the rotating shaft 62d, a light shielding portion 62b for shielding the photo sensor 65 is provided.

As a result, when the second discharge sensor flag 62 protruding into the sheet discharge path 46 is pressed by the sheet and rotates, the rotation shaft 62d rotates, and accordingly, the light shielding portion 62b rotates. It comes to block the photo sensor 65,
Thus, the sheet detecting means 65A including the second discharge sensor flag 62, the light shielding portion 62b, and the photo sensor 65 can detect the leading edge of the sheet.

Incidentally, the second paper discharge sensor flag 62
Is provided with a protruding portion 62a that is substantially horizontal and extends in the sheet discharge direction toward the sheet conveyance direction.
In other words, the tip of the second paper ejection sensor flag 62 has a beak shape bent at approximately 90 °.

Here, a gently curved connecting portion 62c is provided between the protruding portion 62a and a contact surface 62e of the second sheet discharge sensor flag 62 with which the sheet comes into contact. In the present embodiment, R of the communication portion 62c is set to 4.5 (mm). By gently curving the connecting portion 62c in this way, when the sheet presses the second discharge sensor flag 62, the sheet can be prevented from getting caught.

The length Z of the protruding portion 62a in the sheet conveying direction is the length of the hole of the sheet in the sheet conveying direction (hole diameter =
8.0 mm). Further, the width X of the second discharge sensor flag 62 in the width direction orthogonal to the sheet conveying direction is set to be wider than the width (hole diameter) Y of the hole Sh of the sheet S as shown in FIG.

On the other hand, the second paper discharge sensor flag 62 is formed by, for example, die molding. When the second sheet discharge sensor flag 62 is formed by die forming in this manner, when the second sheet discharge sensor flag 62 is formed by the parting line shown in FIG. 62f and 62g are generated.

FIG. 9 shows the second discharge sensor flag 6.
FIG. 4 is an enlarged cross-sectional view of a protruding end portion No. 2, and in the present embodiment, the height W of the step 62 f is set to 0.1 mm or less. In the same figure, an arrow K indicates a normal conveying direction and a discharging direction, an arrow L indicates a conveying direction when the sheet is inverted, and the normal sheet conveying direction and the discharging direction are indicated by an arrow K. For directions,
The step 62f is set to be a step opposite to the normal sheet passing direction (arrow K). That is, the step 62f of the parting line has a lower shape on the sheet reversing direction side opposite to the sheet conveying direction.

Here, FIG.
Second discharge sensor flag 62 when transported toward 0B
When the second ejection sensor flag 62 is pushed down by the sheet S and the second ejection sensor flag 62 falls down, the gap V between the step 62f and the sheet S being fed is secured to some extent. It does not get caught.

Also, by making the parting line step 62f a reverse step, when a perforated sheet is passed through with the hole side as the leading end and turned over, the step 62f becomes a forward step and the hole becomes There is no catch on the step 62f. The configuration of the first discharge sensor flag 61 is the same as the configuration of the second discharge sensor flag 62.

Next, the image forming apparatus 10 having such a configuration will be described.
The copying operation at 0 and the actual movement of the sheet at the paper discharge unit will be described by taking a case where the ADF 102 is used as a pressure plate as an example.

First, in FIG. 3, an original is placed on a contact glass (not shown) on
After closing the button 102, the number of copies and the like are specified by the operation unit 60 (see FIG. 2), and the start button is pressed. Thus, the reading of the document by the scanner unit is started, and the image information of the read document is digitized by photoelectric conversion and subjected to image processing.

Then, the laser writing device of the image forming unit 1 is driven based on the processed signal, and an electrostatic latent image is formed on the photosensitive drum. Thereafter, the latent image is visualized as a toner image, and is transferred to the sheet cassette 21 fed by the sheet feeding unit 2 or a sheet of the sheet feeding table 103. After that, the toner image transferred onto the sheet is fixed by the fixing device 151 and sent to the paper discharge unit 4.

When the sheets are stacked on the discharge tray 41, the driving of the main body vertical path roller 57 is started after a predetermined time as shown in FIG. 11 after the sheets are conveyed to the fixing device 151. As a result, the sheet conveyed from the direction of arrow C passes through the first conveyance path 47 formed by the first flapper 55 located at the position indicated by the solid line, and is discharged from the first discharge roller 51, and is discharged from the first discharge roller 51. Paper tray 41
(See FIG. 4).

On the other hand, when the sheets are to be discharged onto the second discharge tray 42 for sorting, the first flapper 55 is first rotated and moved to the position shown in FIG. Thus, the conveyed sheet S <b> 1 passes through the first flapper 55 and goes to the vertical path roller 54.

After passing through the vertical path roller 54 as shown in FIG. 13, the sheet S1 is conveyed to the sheet discharge path 46 while pushing up the second flapper 56 by stiffness (rigidity), and thereafter as shown in FIG. The paper is discharged by the second paper discharge roller 52 rotating in the direction shown by the arrow, and is stacked on the second paper discharge tray 42.

On the other hand, for sorting, the third paper discharge tray 42
When the sheet S1 is discharged upward, the sheet S1 passes through the vertical path roller 54 as shown in the figure, and is conveyed to the sheet discharge path 46 while pushing up the second flapper 56 by the straining (rigidity) of the sheet S1. When the rear end of S1 passes through the fixing device 151, the conveyance speed of the sheet S1 is increased by 2.5 times after a predetermined time, and at the same time, the driving of the second discharge roller 52 is started.

As a result, as shown in FIG.
Is partially discharged in the direction of arrow D by the second discharge roller 52 rotating in the direction indicated by the arrow. By increasing the transport speed of the sheet S1 by 2.5 times, the sheet S1 to be reversed and the sheet S2 to be transported next are increased.
Can be prevented from interfering with each other.

Thereafter, when the rear end of the sheet S1 conveyed by the second discharge roller 52 passes through the second flapper 56, the second flapper 56 is moved by a spring (not shown) as shown in FIG.
Return to the original standby position as shown in FIG.

Next, based on the timing from the detection of the leading edge of the sheet S1 by the photo sensor 65 (see FIG. 5) calculated according to the size of the sheet S1, it is determined that the rear end of the sheet S1 has reached the reversal point 59a. Then, the second
The driving of the discharge roller 52 is stopped, and after a predetermined time, the second discharge roller 52 starts rotating in the reverse direction.

At the same time, the driving of the third discharge roller 53 is started as shown in FIG. 16, and the sheet S1 is conveyed to the optional discharge path 45. At this time, the transport speed of the second discharge roller 52 and the third discharge roller 53 is a speed increased by 2.5 times. When the sheets are stacked on the third discharge tray 43, the speed increase control is performed in this manner to prevent the collision of the sheets near the second flapper 56 at the time of sheet reversal.

The second discharge roller 52 and the third
The sheet S1 is conveyed in the direction of arrow E by the rotation of the discharge rollers 53, and then, as shown in FIG.
3 is loaded face down. By repeating such an operation, the sheets are sequentially stacked on the third discharge tray 43 in page order.

When images are formed on both sides of the sheet, the sheet S1 conveyed through the electrophotographic process means 150 and the fixing device 151 passes through the first flapper 55, and then, as shown in FIG. Pass roller 57 and first
The sheet is conveyed in the direction of arrow I by the discharge roller 51.

Then, a predetermined time after the trailing end of the sheet S1 is detected by a not shown fixing discharge sensor provided in the fixing device 151, in other words, as shown in FIG. After passing through the three flappers 58 and reaching the reversal point 59, the first discharge roller 51 stops, and after a predetermined time, reverse rotation starts. Thereby, the sheet S1
Is transported to a double-sided path in the direction of arrow J as shown in FIG.

The sheet S1 conveyed to the double-sided path 152 is then conveyed to the selected discharge tray after image formation on the second side is performed. Here, the first discharge tray 4 is used as the discharge tray.
When the first or second discharge tray 42 is selected, the sheet is discharged as it is without performing the reversing operation again. When the third discharge tray 43 is selected as the discharge tray, the sheet S1 is turned over again by the second discharge unit 50B as described above, and then discharged to the third discharge tray 43.

FIG. 2 shows the relationship between the holes in the perforated sheet and the sensor flag when an image is formed on both sides of the sheet or when the sheet is inverted and discharged.
This will be described with reference to FIG.

For example, when the sheet is inverted and discharged, first, as shown in FIG. 20A, the sheet S1 is transported to a position near the second discharge sensor flag 62, and thereafter, the sheet S1 is further transported. Then, as shown in (b), the second discharge sensor flag 62 is pressed in the transport direction by the sheet S1 and starts rotating.

Thereafter, when the sheet S1 is further conveyed, the hole Sh of the sheet S1 passes through the second discharge sensor flag 62 as shown in FIG. 5), when it is determined that the rear end of the sheet S1 has reached the reversal point 58a, the driving of the second discharge roller 52 is stopped, and after a predetermined time, the second discharge roller 52 moves in the reverse direction. Start rotating.

When the hole Sh of the sheet S passes above the discharge sensor flag 62 during the sheet conveyance, the pressing force of the sheet against the discharge sensor flag 62 disappears. While trying to get up, the emission sensor flag 6
2 has a protruding portion 62a having a length Z set in the sheet conveyance direction longer than the length of the hole in the sheet conveyance direction and having a width set wider than the width (hole diameter) Y of the hole in the sheet. Therefore, the sheet S does not enter the hole Sh and does not affect the conveyance of the sheet S.

When the sheet is conveyed toward the second discharge section 50B, if the second discharge sensor flag 62 is pushed down by the sheet and falls down, as shown in FIG. Since the gap V with the sheet S is ensured to some extent, the sheet S does not catch on the step 62f.

Next, the reversal of the sheet S1 is started as described above, and the hole Sh of the sheet S1 is set to the second discharge sensor flag 62.
The second discharge sensor flag 6
2 starts returning to the original position, and a part of the protruding end comes to face the hole Sh as shown in FIG.

However, even if the second discharge sensor flag 62 faces the hole Sh in this manner, the second discharge sensor flag 62 is not closed due to the shape of the protrusion 62 a provided on the second discharge sensor flag 62.
h. In addition, by setting the step 62f of the parting line to an inverted step, when the sheet S is passed through with the hole side as the leading end and turned over, the step S
Is a forward step, so that the hole Sh does not catch on the step 62f. Thus, the sheet S can be reversed and conveyed without being affected by the second discharge sensor flag 62.

Next, after the sheet S1 is further conveyed reversely after the hole Sh faces the second discharge sensor flag 62, the trailing end of the sheet S1 becomes the second discharge sensor flag 6
Exit 2 At the same time, as shown in (b), the second discharge sensor flag 62 starts to return to the original standby position again.
Then, the inverted sheet S1 is conveyed in the direction of arrow E as shown in FIG.
Returns to its original position.

As described above, by forming the protruding portion 62a on the second discharge sensor flag 62, the hole Sh of the sheet S is formed.
The second discharge sensor flag 62 can be prevented from entering due to the urging force of the spring 64, so that when the sheet S is turned over, the sheet S can be prevented from being broken. The same applies to the first discharge sensor flag 61.

[0079]

As described above, according to the present invention, a projecting portion is formed at a projecting end of a lever member projecting into a sheet reversing path so as to detect a sheet, and a sheet conveyed while pressing the lever member. Or after passing through the lever member,
By preventing the lever member from entering the hole of the sheet conveyed in the sheet reversing path in the reversed state, the sheet in which the plurality of holes are formed can be reversed without breaking.

[Brief description of the drawings]

FIG. 1 is a perspective view of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view of the image forming apparatus viewed from another direction.

FIG. 3 is a diagram illustrating a schematic configuration of the image forming apparatus.

FIG. 4 is a cross-sectional view illustrating a paper discharge unit when the optional paper discharge unit is mounted on the apparatus main body.

FIG. 5 is a perspective view of a vicinity of a second discharge unit of the paper discharge unit.

FIG. 6 is a cross-sectional view around the second discharge section.

FIG. 7 is a diagram illustrating a relationship between a width of a second discharge sensor flag provided in the second discharge unit in a width direction orthogonal to a sheet conveying direction and a width of a sheet hole;

FIG. 8 is a side view of the second discharge sensor flag.

FIG. 9 is an enlarged sectional view of a protruding end of the second discharge sensor flag.

FIG. 10 is a diagram illustrating a state of a second discharge sensor flag when a sheet is conveyed toward the second discharge unit.

FIG. 11 is a diagram showing a state when driving of a main body vertical pass roller provided in the optional sheet discharging unit is started.

FIG. 12 is a first diagram illustrating a state in which a sheet is discharged to a second discharge tray provided in the image forming apparatus of the optional discharge unit.

FIG. 13 is a second diagram illustrating a state where sheets are discharged to a second discharge tray of the optional discharge unit.

FIG. 14 is a third diagram illustrating a state in which a sheet is discharged to a second discharge tray of the optional discharge unit.

FIG. 15 is a first diagram illustrating a state in which a sheet is discharged to a third discharge tray of the optional discharge unit.

FIG. 16 is a second diagram illustrating a state where a sheet is discharged to a third discharge tray of the optional discharge unit.

FIG. 17 is a third diagram illustrating a state where a sheet is discharged to a third discharge tray of the optional discharge unit.

FIG. 18 is a first diagram illustrating a state in which images are formed on both sides of a sheet of the optional sheet discharging unit.

FIG. 19 is a second diagram illustrating a state in which images are formed on both sides of the sheet of the optional sheet discharging unit.

FIG. 20 is a first diagram illustrating a relationship between a hole in a perforated sheet and a sensor flag when an image is formed on both sides of the sheet or when the sheet is inverted and discharged.

FIG. 21 is a second diagram illustrating the relationship between a hole in a perforated sheet and a sensor flag when an image is formed on both sides of the sheet or when the sheet is inverted and discharged.

FIG. 22 is a perspective view of the vicinity of a sheet discharge unit provided with a discharge sensor flag of a conventional image forming apparatus.

FIG. 23 is a cross-sectional view of the vicinity of the conventional sheet discharge unit.

FIG. 24 is a plan view of a three-hole sheet in the USA.

FIG. 25 is a first diagram illustrating a relationship between a sheet hole and a discharge sensor flag of the conventional image forming apparatus.

FIG. 26 is a second diagram illustrating a relationship between a sheet hole and a discharge sensor flag of the conventional image forming apparatus.

FIG. 27 is a perspective view showing a state in which a discharge sensor flag has completely entered a hole of a sheet.

FIG. 28 is a table showing the sizes of sheets used in the conventional image forming apparatus.

FIG. 29 is a diagram illustrating a distance between paper discharge rollers when a postcard is transported in the conventional image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming part 2 Paper supply part 4 Paper discharge space 41 First paper discharge tray 42 Second paper discharge tray 43 Third paper discharge tray 44 Optional paper discharge unit 45 Optional discharge path 46 Sheet discharge path 47 First conveyance path 50A 1 discharge unit 50B second discharge unit 50C third discharge unit 51 first discharge roller 52 second discharge roller 53 third discharge roller 55 first flapper 56 second flapper 58 third flapper 61 first discharge sensor flag 62 Second ejection sensor flag 62a Projecting portion 62b Light shielding portion 62c Connecting portion 62d Rotating shaft 62e Contact surface 62f Step 63 Third ejection sensor flag 64 Spring 65 Photosensor 65A Sheet detection means 100 Image forming apparatus 101 Main body 152 Double-sided path S Sheet Sh (Sheet) Hole

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H028 BA09 BA16 2H072 AA32 AB07 BA12 CA01 CA02 FA01 FB02 3F048 AA03 AA04 AB01 BA05 BB10 CC01 DA09 DC01 3F053 BA03 EA03 EA04 EB04 EC02 ED03 LA03 LA05 LB03

Claims (8)

[Claims] 1. An image forming apparatus for forming an image on a sheet having a plurality of holes formed in a width direction orthogonal to a sheet conveying direction, comprising: a sheet reversing path for reversing the sheet; and a sheet reversing path. A sheet detecting means that has a lever member that is pressed by the sheet conveyed to the sheet reversing path and rotates while resisting the urging force, and detects the sheet by the rotation of the lever member; The lever member does not enter into the hole of the sheet conveyed while pressing the lever member or the sheet conveyed in the sheet reversing path in a reversed state after passing through the lever member due to the urging force. The image forming apparatus according to claim 1, wherein a protruding portion is formed at a protruding end of the lever member. 2. The image forming apparatus according to claim 1, wherein the projecting portion is formed on a side of a projecting end of the lever member in a sheet conveying direction. 3. The image forming apparatus according to claim 1, wherein the length of the protrusion in the width direction is set to be longer than the length of the hole of the sheet in the width direction. 4. The image forming apparatus according to claim 1, wherein the length of the protruding portion is set to be longer than the length of the hole of the sheet in the sheet conveying direction. . 5. The protruding end of the lever member is formed so as to be substantially horizontal to the sheet conveying direction when the lever member protrudes into the sheet reversing path. The image forming apparatus according to any one of claims 1 to 4, wherein 6. A gently curved connecting portion is provided between the projecting portion and a contact surface of the lever member with which a sheet comes into contact. Image forming apparatus. 7. The image forming apparatus according to claim 1, wherein the lever member is formed by die molding. 8. The lever member has a parting line on the upper surface of the protruding end, and the level difference of the parting line is reduced toward a sheet reversing direction opposite to the sheet conveying direction. The image forming apparatus according to claim 7, wherein